A constant, direct current drive method is generally employed as a drive method for driving organic EL illuminating devices for light emission. To cause an organic EL illuminating device having a light-emission area of 15 cm square or larger to emit light with a luminance of about 5000 cd/m2, a current with a value of the order of amperes or more needs to be applied on the device. Meanwhile, an inter-electrode resistance between anode and cathode in a non-defective organic EL illuminating device of the above size ordinarily has a value of several MΩ or more; however, the inter-electrode resistance value becomes several tens Ω or less if a short-circuit occurs in a portion between anode and cathode.